Customizable Jack Screw to adjust height of Corners on MPCNC

thingiverse

Update 6/27/2017 I added JackScrew_Test_Rev30.stl and JackScrewMate_Test_0mmClear_Rev30.stl. The ? in the second name denotes clearance amount for internal threads. I uploaded bottom & top flex corners with .4mm clearance, so try test prints first which should take considerably less time to print to make sure this design will work for you. I added following variable: Clearance = 0.4; //clearance to add to Thread OD for internal Threads to the bottom, top & Lock-CornerC openscad files. I have been looking for an easier way to adjust level of corners and came across this idea: https://www.thingiverse.com/thing:953976. Problem was I wanted to use my same corner styles. I did this design in openscad and biggest problem was finding a screw thread library that had some flexibility. Since I am not using a print cooling fan, standard 30 degree angle of threads do not print very well for me. I found this library that gives me the flexibility needed, http://dkprojects.net/openscad-threads/. After some trial & error prints, a thread angle of 40 degrees and a thread pitch of 4 worked for me although internal threads for the bottom parts are not always coming out clean. There is an image showing all my trial & error parts. After playing with some of the printed threaded parts, I thought it might be more useful to make the middle screw shaft a Jack Screw instead. I was originally calling this a turnbuckle but after some research on the Internet looked like it should be called a Jack Screw. It is probably a stronger connection with the original design with that shaft resting at the bottom but I am going to try this as it should not be more than 4mm off the bottom. There is an option in the openscad file to do it either way. I included 3 STL JackScrew version lengths with that option as well as a Flex Foot Bottom for it to fit in. The Jack Screw has a 1/2" EMT in the middle of it. For adjusting the Jack Screw, I included a 32mm plastic wrench and a couple of different style thumbwheels. You can also use a 5mm allen wrench if you do not add the 1/2" EMT to the middle of the Jack Screw. The thumbwheel I modified from: http://www.thingiverse.com/thing:225188. I will add a remix of that separately after I have all these files uploaded. The wrench worked best for me. This is probably obvious but if you use the thumbwheels, you will have to make one for each corner and install it on the Jack Screw before installing the bottom & top parts. There is a lip on the thumbwheels to keep it from dropping below the adjustment nut. I included an image of the variables you can change with the JackScrew_Rev30.scad file as well as a few pictures on the printed parts. I have only installed one corner, but that seems to work pretty good so far. I should be able to start cutting again in a couple of days. Print Data: Flex_Foot_Bottom_M5Bolt_LeftThreads_Rev31.stl Print Time: 2:59:11 at 60% infill 1.02oz Flex_Foot_Top_M5Bolt_RightThreads_Rev31.stl Print Time: 2:58:39 at 60% infill 1.03oz JackScrew_P4_Ang40_100mmHt_Rev30.stl Print Time 100mm Tot_Ht: 5:01:42 at 60% infill 1.5oz Total of 14.2oz of plastic and print time of about 44 hours.